Welcome to the jobs previously completed by Independent Ground Improvement, to find out more about each of these click on one of the links below for full informaiton on each.
The site was the old Hotpoint factory on Westinghouse Road, Trafford Park, Manchester.
Site conditions generally consisted of intermixed loose sand and gravels, with granular fill material, with a large amount of relic foundations still present. In places it was also noted that soft clay/peat deposits were present identified as historic pond areas.
During demolition large concrete slabs and foundations were grubbed up, whilst the ground was remediated down to a depth of 2.5m ensuring all obstacles were cleared. The concrete and masonry works which had previously covered the majority of the site, were then crushed and placed to our backfill specification into the voids created by the remediation. Shallow bands of PEAT were noted and these were delineated in terms of thickness and depth. If the bands were shallow and thick the PEAT was removed, if the bands were thin with a combined thickness of less than 300mm the material was kept in situ.
The methodology was achieved with the close working relationship between the Contractor, the Consulting Engineer and IGI Limited IGI Limited treated the area of the building and foundations to provide 150kN/m2 for foundations and 60kN/m2 for the floor slab. A total of 7695 Vibro stone columns (VSC) to depth ranging between 2.0m and 4.2m, was required to provide the bearing capacity of the development.
The job was on a very tight programme and the requirement for completion of the VSC works was set at 6 weeks. IGI's team completed their works within the time period using only a single rig. Sectional completion of the works was also a stipulation of the contractor in order that they could closely follow our treatment with placement of the foundations, and the steel frame, thus allowing the main contractor to keep ahead of the very tight programme.
The site was the former Neptune Shipyard, bounded to the West by Fisher St and The River Tyne to the East. The Site was to be a new Offshore Wind farm Construction Facility, for Shepherd Offshore Services, consisting of a large single portal frame, car park and hard standing. The factory will be used to develop and build blades for the 'Britannia Project', a 10MW offshore wind turbine prototype under development by Clipper.
Site conditions generally consisted of made ground, generally of a loose to very loose silty sand fill, down to a maximum depth of 6.0m in the area of the development plot, the deepest fill being located close to the dock wall with the Tyne.
The Groundwater was fluctuating with a tidal influence, between 0.98m and 2.20m below the existing ground level. The use of Bottom feed vibro stone columns was used to combat this problem.
The natural ground consisted of loose alluvial silts, found below the made ground and generally between 1.0m and 1.5m in thickness, overlying a firm to stiff laminated CLAY. The depth of the clay shallowed up to 3.0m furthest away from the river Tyne.
During demolition large concrete slabs, piles and foundations were grubbed up, whilst the ground was remediated down to a depth of 2.0m ensuring all obstacles were cleared. The concrete and masonry works which had previously covered the majority of the site, were then crushed and placed to our backfill specification into the voids created by the remediation.
IGI Limited treated the area of the building to 100kN/m2 for the floor slab and hard-standings. The Main foundations were piled, using CFA piles due to uplift forces. A total of 3721 Vibro stone columns (VSC), both top feed and bottom feed methods (with the same rig) to depth ranging between 3.0m and 6.0m, was required to provide the bearing capacity of the development. The job was on a very tight programme and the requirement for completion of the VSC works was set at 4 weeks. IGI's team completed their works within the time period using only a single rig. Sectional completion of the works was also a stipulation of the contractor in order that they could closely follow our treatment with placement of the foundations, and the steel frame, thus allowing the main contractor to keep ahead of the very tight programme.
Lymedale Business Park is a successful development in North Staffordshire and is one mile north of Newcastle-under-Lyme town centre, adjacent to the A34 with excellent road links to the A500, A50 and M6 motorway at Junctions 15 and 16. Lymedale Cross has a 415,000sqft speculative unit now under construction.
The proposed building plot was initially split with half the building being formed by the demolished building with the hardstanding concrete slab still remaining, with the other half of the building formed by the football field at a level ranging from the same as the slab, to nearly 2.0m above the slab level.
The job involved a major cut and fill operation, along with ground improvement in the form of lime modification, and vibro stone columns.
The job involved initially breaking up the old building slab and stockpiling this material. The site was then upfilled primarily using the material taken from the cut area of the site, and then with material taken from a borrow pit. The borrow pit was excavated in an area designated as open space use, for the primary objective of burrying Japanese Knotweed, found in one corner of the building plot. The design and execution of this was carried out and at all times was overseen by a Japanese Knotweed expert.
The initial material from the borrow pit, and the cut area of the development was generally a clay soil and in this instance the material required modification with lime to achieve the 5% CBR required as part of the ground improvement design.
As the borrow pit was deepened the material became a sandstone/marl material which when excavated was primarily of a granular nature. This material was used in preferance to the clay material, and subsequently the site was not full stripped due to the inclement weather conditions during this period allowing the site to progress during the wet and cold weather and the material placed at 5% CBR by the earthworkers but without the need for the inclusion of an adative (Lime).
The cohesive cut material was then placed in the borrow pit on top of the Japanese Knotweed, and rolled into place, but not to a specific specification.
Once at the formation level the site was then treated in the entire fill area with vibro stone columns (VSC) to bepth below the original ground level. The VSC spacing was adapted to account for the differences in fill thickness, and the underlying soils, and feathered out in to the cut area to provide a gradual transition from the fill to cut areas. Parts of the cut area exhibited material suitable for founding the structure without the need for ground improvement, and due to the feathering outexersice, the foundations and floor slabs were carried out using traditional methods.
The job was carried out within a 10 week period, in which circa 6,950 columns were placed, varying in depth between 2.0m and 4.5m.
The area of the building was designed to be stabilised to a 15% CBR for the upper 300mm, this was replaced by crushed concrete won from the site during the demolition.
The job was only able to be carried out by a close working relationship between ourselves the contractor and the groundworker.